(a) Field of the Invention
The present invention relates to an input current regulator, a driving method thereof, and a circuit that disables an input current regulator.
(b) Description of the Related Art
A triac dimmer passes each cycle of a sine wave of an AC input by a dimming angle. In order to maintain the triac dimmer in a turn-on state, more than a predetermined holding current should flow through the dimmer.
When a current (hereinafter, referred to an input current) flowing through the dimmer is smaller than the holding current, the dimmer is turned off. When the input current is iteratively greater than or smaller than the holding current, the dimmer is iteratively turned on/off, causing flicker.
In order to prevent occurrence of flicker, a bleeder is used to maintain the input current to be greater than the holding current. The bleeder is provided between the dimmer and a power supply. In this case, a rectification circuit may be disposed between the dimmer and the bleeder.
A typical bleeder senses an input voltage passed through the rectification circuit and determines the input current to be smaller than the holding current when the sensed input voltage is lower than a predetermined reference level. When the input current is determined to be smaller than the holding current, the bleeder generates a current to compensate a difference of the two currents.
The current generated by the bleeder is not a current varying to compensate the difference of the two currents but a constant current. Thus, a current remaining after compensation of the difference of the two currents is wasted. Due to increase of power consumption, an operation temperature of the bleeder is increased.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.